1. Technical Field
The present invention relates to a density determination method, a density determination apparatus, a density determination program, and a program recording medium that, in a printing technology for printing an image on a medium, determine a maximum value of the density of the image.
2. Related Art
In printing apparatuses that perform printing of an image on a medium by discharging inks onto the medium, the higher the density of colors obtained by the respective inks is, the higher the ability of representing the image is, and as a result, the realization of high image quality printing is facilitated. When, however, a density upper limit value is not provided, the amount of the discharged inks exceeds the ink absorption amount of the medium, and as a result, problems, such as unclearness of edge portions of an output image due to the blurring and leaking of the inks, and the degradation of the reproducibility of lines and letters, occur. Thus, in a conventional way, the density upper limit value has been determined by printing a plurality of colorimetric patches having mutually different densities on a medium, and visually determining the printed colorimetric patches. This density upper limit value differs depending on a medium type. For example, the density upper limit value is high for a medium whose ink absorption amount is relatively high, and the density upper limit value decreases as the ink absorption amount decreases. In addition, in this specification, a density upper limit value that enables printing on the medium to be performed without causing any one of the above problems will be hereinafter referred to as “a maximum printing density value for the medium”.
When the maximum printing density value for a medium is obtained by the visual determination, it is inevitable that individual differences exist among the results of determinations made by persons responsible for the visual determination. The reproducibility, therefore, may be a disadvantage of the above conventional technology. Thus, for example, a technology disclosed in JP-A-2005-238465 has been proposed as a technology to be applied in substitution for the visual determination. This technology disclosed in JP-A-2005-238465 is a technology in which OD values of individual colorimetric patches are detected by colorimetry equipment and a maximum printing density value is determined on the basis of the result of the detection.
According to the technology disclosed in JP-A-2005-238465, however, there is a need for printing the colorimetric patches having various densities. Thus, in a high density patch region where colorimetric paths each having a relatively high density are printed among a surface region of a medium, one or more unfavorable phenomena in relation to ink, such as cockling, leaking of ink, and dripping of ink, are likely to occur. The cockling is a phenomenon in which the medium absorbs a large amount of ink and, as a result, the printing region on the surface of the medium becomes an undulant state. The occurrence of such one or more phenomena may bring the medium into contact with a head of a printing apparatus, may cause ink having dripped from the medium to be adhered to the printing apparatus, and/or may stain an installation place of the printing apparatus.